In 2006, having already started work as a parliamentary researcher, she completed her thesis entitled Understanding the lifeworld of social exclusion,[9] receiving a doctorate in Social Psychology from the London School of Economics.[7] Creasy received a Titmuss Prize in 2005 for her thesis.[10]

Creasy served on Labour's Business, Innovation & Skills front bench team.[17] She has been described as "one of the brightest lights of Labour's new generation" and as not being "the sort of politician to criticise her own leader".[18]

Creasy regularly writes for Progress,[19] a movement of centre-left Labour party members and supporters.[20]

Creasy has campaigned for better regulation of payday loans companies.[21] In an article published by The Guardian, she stated that just six companies controlled lending to 90% of the seven million Britons without a bank account or credit card. Her disclosure that the average cost of credit charged to these customers was 272% APR, as in the rest of Europe, and that there was a fourfold increase in payday loans since the start of the recession in 2008 led to cross-party parliamentary support for a cap.[21] Creasy also highlighted in a speech to the House of Commons the lack of competition in the market, leading to Government support for a cap of loans which exploit the poor, which in some cases reached 4000%. APR.[22] Creasy won The Spectator magazine's Campaigner of the Year prize in their Parliamentarian of the Year awards in 2011 for her work on the issue.[23]

In 2012, a Wonga employee used company equipment to make offensive personal attacks against Creasy.[24] Wonga made an "immediate and unreserved apology" following these malicious attacks, and Creasy also managed to get the firm to promote one of her constituency events in aid of struggling families.[24]

Creasy wrote in an article published on 27 July: "Twitter tell me we should simply block those who 'offend us', as though a rape threat is matter of bad manners, not criminal behaviour."[26] She also appeared on Newsnight on 30 July 2013 with Toby Young, the Conservative commentator, over the validity of addressing harassment on the social networkingsite.[27][28] She criticised him for a previous tweet about an MP's breasts.[29] Young has objected to Twitter's subsequent change in policy, writing that the company, "shouldn't change its abuse policy in response to being brow-beaten by a politician".[30] On 2 September 2014 at the City of London Magistrates' Court, Peter Nunn was found guilty of sending menacing messages to Creasy,[31] and was subsequently jailed for eighteen weeks.[32]

Creasy did not back any of the final four candidates in the leadership election.[35] She stated that she was prepared to work as a deputy to any of the candidates for the party leadership, including Jeremy Corbyn.[36] "Of course I would", she told Carol Midgley in a Times interview in August 2015, "because that process of rebuilding isn’t about any one person it's about all of us. It's written on the back of our membership card that we achieve more together than we do alone."[37] However, she is a vocal and prominent critic of Labour leader Jeremy Corbyn, stating that she has no confidence in him.[38]

In late 2015, members of the Momentum group were accused of aiming to replace Creasy with someone closer to the Labour left.[39] A possibility that the seat might be redrawn after boundary changes means potential candidates are jockeying for position in the constituency party. Momentum have denied this claim.[39] Creasy has criticised Momentum.[40]

Creasy allegedly received threats via social media following her vote for extending UK military action against ISIS to Syria after the parliamentary debate on 2 December 2015.[41] Creasy was undecided until the day of the vote, while staff in her Walthamstow constituency office had to deal with what they referred to as harassing telephone calls.[42] Protesters had gathered outside the office the previous night urging a 'no' vote.[41][42] On Facebook, Creasy defended their right to peaceful protest.[43] Reports that protesters had gathered outside her home proved to be unfounded.[44][45]

Abortion law in Northern Ireland is more restrictive compared to the rest of the United Kingdom, resulting in many women travelling from Northern Ireland to Great Britain to access abortion services. In 2017, a potential amendment to the Queen's Speech, organised by Creasy, calling for the Government to allocate adequate funding for women who are forced to travel to England to have an abortion, gained cross-party support and was ultimately signed by 100 MPs threatening a government defeat.[48]Conservative MP Peter Bottomley was a co-signer of Creasy's amendment. In answer to a question from Bottomley in the Commons on 29 June 2017, Philip Hammond, Chancellor of the Exchequer, said the government would support free abortions on the mainland for Northern Irish women.[49][50]

Earlier in June, a Supreme Court ruling upheld the legal basis for a charge of £900 for women from the province seeking an abortion on the mainland, whereas other necessary treatments on the NHS would have been free.[49][51] Creasy was cautious in her response to the development. "The devil will be in the detail", she said.[50] She was reported to have received threats from some anti-abortion activists.[52][53]

Additionally, Creasy criticised Corbyn for his call to decriminalise the sex industry.[54]

^ abSome sources suggest Creasy was born on 1 January 1977. Her father, in a letter to The Guardian, confirmed that 5 April is the correct date. See "Brief Letters: Plaque Russians", The Guardian, 8 January 2013